1. Field of the Invention
This invention pertains to the field of electronics. In greater particularity, this invention pertains to microwave electronic circuitry. By way of further characterization, but without limitation thereto, this invention pertains to the modulation of magnetron oscillators. More specifically the invention will be described as it pertains to the generation of extremely short pulses of coherent microwave energy.
2. Description of the Prior Art
The development of high-resolution radar systems and other radar applications where high-resolution is desired, the use of short pulse duration transmitting modes have achieved popularity because of the reduction of minimum range coverage and high-target resolution. Great strides have been made in recent years in short-pulse operation by using pedestal pulse modulators. Examples of which are shown in U.S. Pat. No. 3,273,075 issued Sep. 13, 1996 to H. L. Kennedy for “Pulse Generator System Providing Pulse Superimposed On A Pedestal” and in U.S. Pat. No. 4,051,439, issued Sep. 27, 1997 to Reuben E. Nyswander for “Short Pulse Magnetron Transmitter”.
Another approach for radar signal processing employs coherent transmitted pulses which make possible much more target information than can be-obtained with a non-coherent system. For example, coherent pulses permit processing to obtain Doppler information indicative of target movement. Such arrangements have applications in synthetic aperture systems and moving target indicating systems. Heretofor, obtaining coherence in transmitting radar systems have ranges of coherence limited to approximately 10 Mz. Naturally, such limitations are reflected in limitations of application which could be vastly improved if coherence could be obtained over a wider frequency range.